results similar with the previous studies, In addition, batting the difference between static and dynamic sphere caused the bat swing velocity reduction val-ues of this study showed slightly lower of the phenomenon.
Acknowledgements: The authors would like to acknowledge Taiwan National Science Council (NSC100-2622-H-154-001-CC3) to provide the funding.
ID: 655 PO-03: 52
Accurate measurement of the kinematics of the knee during cycling exercise using a 3D fluoroscopy method Shih-Wun Hong1, Tung-Wu Lu1,2, Cheng-Chung Lin1, Jia-Da Li1,
Yu-Huan Wu1, Yen-Hung Liu1,3, Mei-Ying Kuo4and
Horng-Chaung Hsu5
1Institute of Biomedical Engineering, National Taiwan University,
Taiwan; 2Department of Orthopaedic Surgery, School of Medicine,
National Taiwan University, Taiwan; 3Department of Physical
Therapy, Tzu Hui Institute of Technology, Taiwan; 4School of
Physical Therapy, China Medical University, Taiwan; 5Department
of Orthopaedics, China Medical University Hospital, Taichung, Taiwan.
Introduction:Cycling exercises have been used in the rehabilitation of the lower extremities especially in patients with cruciate ligament injuries or reconstruc-tion. Knowledge of the kinematics of the knee under different pedaling patterns may help develop injury-specific cycling exercises to reduce the risk of overuse injuries and to improve the recovery rate. Therefore, the current study aimed to measure the 3D skeletal kinematics of the knee during cycling using a 3D flu-oroscopy method under different pedaling patterns. Methods: Eleven healthy young adults wearing 14 markers on the right lower limb performed cycling exercises on an ergometer with the feet placed on the pedals at neutral position, 10 degrees of inversion, and 10 degrees of internal rotation while the skeletal motions of the knee were imaged by a fluoroscopy system (ALLURA XPER FD, Philips). The knees of the subjects were also CT scanned and used to con-struct CT-based bone models, which were then registered to the fluoroscopy images using a fluo-roscopy-to-CT registration method, giving the rotations, translations and articular contact kinemat-ics of the knee. A one-way analysis of variance was used to analyze the effects of pedaling patterns on each of the variables (α=.05).
Results and Discussion:Accurate 3D skeletal kine-matics of the knee during cycling was measured for first time in the literature. Significantly increased
knee flexion was found in cycling exercises with the foot internal rotated. Significantly decreased contact areas of the knee in both medial and lateral compart-ments were found in the conditions of inverted or internal rotated foot placement. Decreased contact areas associated with inadequate foot placement may lead to abnormal pressure distributions in the articular surfaces during cycling, which may be a risk factor of failure of the knee articular cartilage.
ID: 659 PO-03: 53
Effect of extracellular matrix proteins on fluid shear stress-mediated stem cell differentiation
Surabhi Sonam and Chwee Teck Lim
Mechanobiology Institute, National University of Singapore, Singapore.
Previous studies show that stem cells growing on indi-vidual extracellular matrix proteins (ECM) proteins follow different lineages. Different integrin molecules attach to different ECM proteins and in turn activate differentiation pathways. However, under the effects of mechanical loading, differentiation patterns followed by cells seeded on different ECM proteins has not been well understood. Here, human Mesenchymal Stem Cells (hMSCs) were subjected to fluid shear stress (FSS) while growing on different ECM proteins: collagen, fibronectin and laminin. Cells seeded on collagen or fibronectin coated channels showed increased cell con-tractility with time. However, no change in concon-tractility was observed in those seeded on laminin. Presence of osteogenic marker, osteopontin, showed that the cells followed osteogenic lineage on collagen and fibronectin but not on laminin. The cells also spread more on collagen and fibronectin than that on laminin. This change in spreading area of the cells can modulate the contractility and cytoskeletal arrangement of the cell on different ECM proteins which may lead the cells towards different lineages. To better understand the phenomenon, cells will be grown on ECM patterns of different sizes to control the spreading area of the cells while being exposed to FSS. Also, cells will be subjected to FSS while growing on decellularised matrices obtained from rat bone tissue and fat tissue, which have different ECM compositions. This would allow the cells to grow on tissues with different stiffness allowing different spreading areas to the cells. This study focuses on elucidating the role of ECM proteins in shear stress-mediated stem cell differentiation.
